Influence of Grounding Wires on Measured Frequency-Dependent Soil Properties

Calculations and measurements show that the grounding wires can significantly influence measured frequency-dependent soil properties (resistivity and permittivity). The smaller the distance between the grounding wire and the measurement setup, the larger the measurement error. In order to improve measurement accuracy, one should determine the minimum distance for which the measurement error can be neglected. The work proposes and experimentally validates the simulation model based on the finite-difference time-domain method. The model allows changing the grounding wire position relative to the measurement setup and estimating the measurement error. It has been demonstrated that a distance of about 1.5 m between the wire and the array is sufficient to neglect the measurement error.